A European Database of Fusarium graminearum and F. culmorum Trichothecene Genotypes

Abstract

Fusarium species, particularly Fusarium graminearum and F. culmorum, are the main cause of trichothecene type B contamination in cereals. Data on the distribution of Fusarium trichothecene genotypes in cereals in Europe are scattered in time and space. Furthermore, a common core set of related variables (sampling method, host cultivar, previous crop, etc.) that would allow more effective analysis of factors influencing the spatial and temporal population distribution, is lacking. Consequently, based on the available data, it is difficult to identify factors influencing chemotype distribution and spread at the European level. Here we describe the results of a collaborative integrated work which aims (1) to characterize the trichothecene genotypes of strains from three Fusarium species, collected over the period 2000-2013 and (2) to enhance the standardization of epidemiological data collection. Information on host plant, country of origin, sampling location, year of sampling and previous crop of 1147 F. graminearum, 479 F. culmorum, and 3 F. cortaderiae strains obtained from 17 European countries was compiled and a map of trichothecene type B genotype distribution was plotted for each species. All information on the strains was collected in a freely accessible and updatable database (www.catalogueeu.luxmcc.lu), which will serve as a starting point for epidemiological analysis of potential spatial and temporal trichothecene genotype shifts in Europe. The analysis of the currently available European dataset showed that in F. graminearum, the predominant genotype was 15-acetyldeoxynivalenol (15-ADON) (82.9%), followed by 3-acetyldeoxynivalenol (3-ADON) (13.6%), and nivalenol (NIV) (3.5%). In F. culmorum, the prevalent genotype was 3-ADON (59.9%), while the NIV genotype accounted for the remaining 40.1%. Both, geographical and temporal patterns of trichothecene genotypes distribution were identified.

Keywords: Fusarium; acetyldeoxynivalenol; chemotype; database; genotype; mycotoxin; nivalenol; trichothecene.

Figure 1

Spatial distribution of chemotypes and Fusarium species in Europe. 3-ADON, 3-acetyldeoxynivalenol; 15-ADON, 15-acetyldeoxynivalenol; NIV, nivalenol. F. cortaderiae were isolated in Italy but cannot be visualized as they are overlapped by other strains.

Figure 2

(A) Spatial distribution of Fusarium culmorum chemotypes in Europe. Red squares, genetic 3-ADON chemotype. Yellow squares, genetic NIV chemotype. (B) Spatial distribution of Fusarium graminearum sensu stricto chemotypes in Europe. Green circles, genetic 15-ADON chemotype. Red circles, genetic 3-ADON chemotype. Yellow circles, genetic NIV chemotype.

Figure 3

Frequency distributions of (A) the years, when the fungal strains for the current database were isolated, (B) the countries of origin of the strains, (C) the host plants from which strains were isolated, (D) the previous crops (“Other” include mixtures of legumes and cereals, lucerne, lupines, perennial forages, spinach, and sugar beet), and (E) the species/chemotype combinations found. Only 3 Fusarium cortaderiae strains were included and are thus not visible in this figure. In the host plant figure, “other crops” include thistles, soya and potatoes. “Other poaceae” include forage grasses, einkorn wheat, triticale, wild type barley.

Figure 4

Materials from which the fungal strains were isolated.

Figure 5

Multiple correspondence analysis (MCA) with year, country, crop. The two major components are plotted. Dimension 1 accounted for 6.66% of the variance in the data and dimension 2 accounted for 5.55% of the variance. Both dimensions reflect levels of association between the categories of the factors rather than the factors themselves. Groups of objects being close to each other share many properties, while objects (in our cases Fusarium strains) being distant, do not share many properties. If distinct groups occur in the plot, the data set contains enough information to separate the groups based on the categorical data that entered the MCA. If all groups are intermixed, the variables that entered the MCA are not suitable to distinguish the groups. (A) Colors indicate different Fusarium species (black, Fusarium graminearum; blue, Fusarium culmorum). (B) Colors indicate different chemotypes (black, 3-ADON; blue, NIV; violet, 15-ADON).

Figure 6

Presence (=1) and absence (=0) of different chemotype strains within the European Fusarium graminearum sensu stricto and F. culmorum isolate collection in relation to the latitude where they were found. (A) 15-ADON chemotype strains in F. graminearum. (B) NIV chemotype strains in F. graminearum. (C) NIV chemotype strains in F. culmorum. The logistic regression line gives an estimate about the probability of finding a particular isolate within the F. graminearum/F. culmorum population.